WARNING: This page is about a different car, the 2016 Hyundai Elantra GT and 2015 Hyundai Elantra GT. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: Audio Unit Troubleshooting Flow Chart 1 (1 Of 2)
Courtesy of HYUNDAI MOTOR AMERICA
Fig 2: Audio Unit Troubleshooting Flow Chart 1 (2 Of 2)